  // Author: Hoang Tran (https://www.facebook.com/profile.php?id=100004848287494)
  // Github verson (1 file .html): https://github.com/HoangTran0410/3DCarousel/blob/master/index.html


  // You can change global variables here:
  var radius = 240; // how big of the radius
  var autoRotate = true; // auto rotate or not
  var rotateSpeed = -60; // unit: seconds/360 degrees
  var imgWidth = 120; // width of images (unit: px)
  var imgHeight = 170; // height of images (unit: px)
  // var bgMusicURL = 'https://api.soundcloud.com/tracks/143041228/stream?client_id=587aa2d384f7333a886010d5f52f302a';
  // var bgMusicControls = true; // Show UI music control
  setTimeout(init, 1000);

  var odrag = document.getElementById('drag-container');
  var ospin = document.getElementById('spin-container');
  var aImg = ospin.getElementsByTagName('img');
  var aVid = ospin.getElementsByTagName('video');
  var aEle = [...aImg, ...aVid]; // combine 2 arrays

  // Size of images
  ospin.style.width = imgWidth + "px";
  ospin.style.height = imgHeight + "px";

  // Size of ground - depend on radius
  var ground = document.getElementById('ground');
  ground.style.width = radius * 3 + "px";
  ground.style.height = radius * 3 + "px";

  function init(delayTime) {
    for (var i = 0; i < aEle.length; i++) {
      aEle[i].style.transform = "rotateY(" + (i * (360 / aEle.length)) + "deg) translateZ(" + radius + "px)";
      aEle[i].style.transition = "transform 1s";
      aEle[i].style.transitionDelay = delayTime || (aEle.length - i) / 4 + "s";
    }
  }

  function applyTranform(obj) {
    // Constrain the angle of camera (between 0 and 180)
    if (tY > 180) tY = 180;
    if (tY < 0) tY = 0;

    // Apply the angle
    obj.style.transform = "rotateX(" + (-tY) + "deg) rotateY(" + (tX) + "deg)";
  }

  function playSpin(yes) {
    ospin.style.animationPlayState = (yes ? 'running' : 'paused');
  }

  var sX, sY, nX, nY, desX = 0,
    desY = 0,
    tX = 0,
    tY = 10;

  // auto spin
  if (autoRotate) {
    var animationName = (rotateSpeed > 0 ? 'spin' : 'spinRevert');
    ospin.style.animation = `${animationName} ${Math.abs(rotateSpeed)}s infinite linear`;
  }

  // setup events
  document.onpointerdown = function (e) {
    clearInterval(odrag.timer);
    e = e || window.event;
    var sX = e.clientX,
      sY = e.clientY;

    this.onpointermove = function (e) {
      e = e || window.event;
      var nX = e.clientX,
        nY = e.clientY;
      desX = nX - sX;
      desY = nY - sY;
      tX += desX * 0.1;
      tY += desY * 0.1;
      applyTranform(odrag);
      sX = nX;
      sY = nY;
    };

    this.onpointerup = function (e) {
      odrag.timer = setInterval(function () {
        desX *= 0.95;
        desY *= 0.95;
        tX += desX * 0.1;
        tY += desY * 0.1;
        applyTranform(odrag);
        playSpin(false);
        if (Math.abs(desX) < 0.5 && Math.abs(desY) < 0.5) {
          clearInterval(odrag.timer);
          playSpin(true);
        }
      }, 17);
      this.onpointermove = this.onpointerup = null;
    };

    return false;
  };

  document.onmousewheel = function (e) {
    e = e || window.event;
    var d = e.wheelDelta / 20 || -e.detail;
    radius += d;
    init(1);
  };
